<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>margin问题1</title>
    <style>
        .outer{
            width: 400px;
            height: 400px;
            background-color: green;
            padding: 20px;
        }
        .inner{
            width: 100px;
            height: 100px;
            margin: 100px;
            background-color: orange;
        }
    </style>
</head>
<body>
    <div class="outer">
    <div class="inner"></div>
</div>
</body>
</html>